FIELD
[0001] The present disclosure relates to a liquid applicator for applying a liquid to a
surface, e.g., a surgical prep applicator. In particular, the present disclosure relates
to a liquid applicator having a lever suitable for crushing an ampoule and releasing
liquid within the applicator.
SUMMARY
[0002] Briefly, in one aspect, the present disclosure provides a liquid applicator for applying
a liquid to a surface. Generally, the applicator comprises an elongated hollow body
comprising a wall defining an internal chamber having a closed end and an open end;
wherein the wall comprises a handle region and a crush region and wherein the ratio
of thickness of the wall in the crush region over the thickness of the wall in the
handle region is less than 1. A first ampoule formed of a frangible material is located
in the internal chamber proximate the crush region and containing the liquid. A lever
is integral with the hollow body and comprises a hinge projecting from a first location
attached to the hollow body to a second location, a grip extending from the second
location to a third location, and a foot integral to the wall adjacent the crush region.
The lever comprises a first truss extending from the third location to the foot; a
second truss extending from the second location to the foot, and a brace connecting
the hinge and the second truss. The width of the first truss is tapered from a first
width proximate the third location and a second width proximate the foot; wherein
the ratio of the second width over the first width is less than 1.
[0003] In some embodiments, the width of the second truss is tapered from a third width
proximate the second location to a fourth width proximate the foot; wherein the ratio
of the fourth width over the third width is less than 1. In some embodiments, the
brace is substantially parallel to the major axis of the elongated hollow body.
[0004] The above summary of the present disclosure is not intended to describe each embodiment
of the present invention. The details of one or more embodiments of the invention
are also set forth in the description below. Other features, objects, and advantages
of the invention will be apparent from the description and from the claims. The invention
is defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005]
FIG. 1 illustrates a side view of one exemplary liquid applicator according to some embodiments
of the present disclosure.
FIG. 2 illustrates a cross section of the exemplary liquid applicator of FIG. 1.
FIG. 3 illustrates a side view of one exemplary lever corresponding to the lever of the
exemplary liquid applicator of FIG. 1.
FIG. 4a illustrates a cross section of the exemplary lever of FIG. 3, before crushing.
FIG. 4b illustrates a cross section of the exemplary lever of FIG. 3, after crushing.
FIG. 5 illustrates an end view of the exemplary lever of FIG. 3.
FIG. 6a illustrates another exemplary lever according to some embodiments of the present
disclosure.
FIG. 6b illustrates yet another exemplary lever according to some embodiments of the present
disclosure.
DETAILED DESCRIPTION
[0006] Antiseptic preparation of patient's skin for surgery conventionally includes a 3-10
minute scrubbing of the affected area with an antiseptic soap solution followed by
the application of a water-soluble antiseptic paint solution. These solutions have
been applied with saturated sponges that are attached to a blade or held with forceps.
These sponges are often saturated by soaking them in open pans of solution. While
inexpensive, these techniques are messy and offer little control over inadvertent
dripping of the solution into areas where it is undesired.
[0007] Alternatively, devices have been developed in an attempt to prevent solution dripping
associated with these techniques, and to reduce the time required for application
of the antiseptic solution. For example, liquid applicators that hold the liquid in
a frangible ampoule and require additional elements to crush the ampoule and release
the liquid have been developed. However, existing applicators are often complex to
construct and may be difficult or cumbersome to use.
[0008] For example, some liquid applicators use a multipart design. By manufacturing the
lever separate from the hollow body, different materials may be used to achieve the
desired results. For example, typically the hollow body is formed of a flexible, low
modulus material such as low density polyethylene. In contrast, the lever is typically
formed of a more rigid, higher modulus material such as high density polyethylene
or polycarbonate. With such selections, the force applied to the lever will be sufficient
to compress the hollow body and fracture the ampoule before the lever itself is significantly
deformed. However, such a two-part structure is more complex to manufacture.
[0009] Other liquid applicators use a one-part design. Here, a lever is integrally formed
with the hollow body. The lever includes a hinge, a grip, and a foot. If properly
designed, when the grip is depressed, it will rotate about the hinge, causing the
foot to compress the hollow body and fracture the ampoule releasing the liquid. The
integral design of such applicators is simpler to construct; however, only a single
material can be used for the entire construction. In such prior art applicators, rigid,
high modulus materials have been chosen to ensure the force applied to lever will
be sufficient to compress the hollow body and fracture the ampoule before the lever
itself is significantly deformed. This requirement has led to designs that include
the use of awkward and less efficient non-cylindrical hollow body designs. Even with
such modifications, these applicators may be difficult to operate.
[0010] WO 2013/162882 A1, which is a document under Art. 54(3) EPC, discloses a liquid applicator for applying
a liquid to a surface. The applicator comprises an elongated hollow body comprising
a wall defining an internal chamber having a closed end and an open end. The wall
comprises a handle region and a crush region. The ratio of thickness of the wall in
the crush region over the thickness of the wall in the handle region is less than
1. The applicator of
WO 2013/162882 A1 further comprises a first ampoule formed of a frangible material located in the internal
chamber proximate the crush region and containing the liquid. The applicator comprises
a lever integral with the hollow body and comprising a hinge projecting from a first
location attached to the hollow body to a second location, a grip extending from the
second location to a third location, and a foot integral to the wall adjacent the
crush region. The lever comprises a first truss extending from the third location
to the foot; a third truss extending from the second location to the foot, and a second
truss between the first and third trusses and extending from the foot to a fourth
location, between the second and third location. The width of the first truss is tapered
from a first width proximate the third location and a second width proximate the foot.
The ratio of the second width over the first width is less than 1.
[0011] An exemplary liquid applicator according to one embodiment of the present disclosure
is illustrated in
FIG. 1. Liquid applicator
100 comprises elongated hollow body
110 comprising wall
160. Wall
160 defines chamber
170 having closed end
172 and open end
174. Closed end
172 may be sealed in any of a variety of known ways to inhibit or prevent fluid contained
within the chamber from escaping through the closed end. For example, cap
118, which may be press-fit, screwed or otherwise attached, may seal the chamber forming
closed end
172.
[0012] Open end
174 allows fluid to flow from the hollow body and be applied where desired. In some embodiments,
pad
178 may be attached to the open end to control the flow rate and distribution of the
fluid. Pad
178 may be formed of any suitable, porous substance including, e.g., sponge, woven and
nonwoven materials, screens, meshes and combinations thereof. A wide variety of known
materials can be used in the construction of the pad including, e.g., polyester polyurethane
and polyester polyether open cell foams.
[0013] In some embodiments, such as the one shown in
FIG. 1, open end
174 terminates in flange
177, which provides a mating surface for pad
178. In addition, flange
177 may include features such as ribs, holes, and channels to aid in the control and
distribution of the flow. The pad can be attached to the flange by known means including,
e.g., adhesives and ultrasonic welding.
[0014] Ampoule
180 is located within chamber
170. Generally, the ampoule is formed of a frangible material, e.g., glass. Such materials
are relatively brittle and will fracture when compressed. This is in contrast to relatively
flexible materials that would deform when compressed but which must be punctured to
release the liquid inside. In some embodiments, score lines or other features that
provide local areas of weakness in the frangible material may be included to control
breaking and/or reduce the force required to break the ampoule.
[0015] The size and shape of the ampoule is selected to be compatible with the dimensions
of the internal chamber and the desired volume of liquid. For example, for use in
preparation for a small surgical procedure, the amount of liquid in the ampoule should
generally be sufficient to cover an area of, e.g., 10 square centimeters or more.
For larger surgical procedures, the amount of liquid in the ampoule may need to be
sufficient to cover at least the torso of a large person, e.g., at least about 500-600
square centimeters.
[0016] Ampoule
180 contains the liquid to be dispensed. Generally, any liquid can be contained within
the ampoule, with the selection of the liquid influencing the selection of the materials
used to construct the ampoule and other parts of the applicator, as understood by
one of ordinary skill in the art. In some embodiments, the applicator may be particularly
useful in dispensing liquids having viscosities at room temperature of less than about
10,000 cps, most preferably less than about 500 cps.
[0017] In some embodiments, the ampoule may contain an antiseptic preparation. Examples
of suitable antiseptic preparations include those described in
U.S. Patent No. 4,584,192 and those described in
U.S. Patent No. 4,542,012. Other useful fluids include antiseptic preparations, e.g., iodophoric skin tinctures,
such as "Duraprep™ Surgical Solution," commercially available from 3M. In some embodiments,
the ampoule be filled with a composition that includes an antimicrobial agent such
as iodine, an iodine complex (e.g., iodophors), chlorhexidine, chlorhexidine salts
(e.g., chlorhexidine digluconate and chlorhexidine diacetate), or combinations thereof.
Other exemplary antimicrobial agents include C2-C5 lower alkyl alcohols, fatty acid
monoesters of glycerin and propylene glycol, polymers that include a (C12-C22) hydrophobe
and a quaternary ammonium group, polyquaternary amines (e.g., polyhexamethylene biguanide),
quaternary ammonium silanes, silver, silver salts (such as silver chloride), silver
oxide and silver sulfadiazine, methyl, ethyl, propyl and butyl parabens, octenidene,
peroxides (e.g., hydrogen peroxide and benzoyl peroxide), and the like, as well as
combinations thereof.
[0018] Liquid applicator
100 also comprises lever
130 comprising hinge
132, grip
134, and foot
136. Hinge
132 extends from first location
142, which is integral to hollow body
110, to second location
144. Grip
134 continues the lever from second location
144 to third location
146. Trusses
151 and
155 connect hinge
132 and grip
134 to foot
136. First truss
151 extends from third location
146 to foot
136. Similarly, second truss
155 extends from second location
144 to foot
136.
[0019] Lever
130 also includes brace
157 connecting hinge
132 with second truss
155. Brace
157 is integral to hinge
132, intersecting hinge
132 at a location between first location
142 and second location
144. In some embodiments, brace
157 intersects hinge
132 about midway between first location
142 and second location
144, e.g., in some embodiments, brace
157 intersect hinge
132 within +/- 20% of the midpoint, or even within +/- 10% of the midpoint of hinge
132, based on the length of the hinge.
[0020] Brace
157 is also integral to second truss
155, intersecting second truss
155 between foot
136 and second location
144. In some embodiments, brace
157 intersects second truss
155 about midway between foot
136 and second location
144, e.g., in some embodiments, brace
157 intersect second truss
155 within +/- 20% of the midpoint, or even within +/- 10% of the midpoint of second
truss
155, based on the length of the second truss.
[0021] Additional features suitable for use in some embodiments are shown in
FIG. 2, which illustrates a cross section of the exemplary applicator
100 of
FIG. 1. For example, cap
118, which is press-fit onto hollow body
110, includes optional prongs
119 which conform to the end of ampoule
180 holding in place. Wall
160 includes optional ribs
161 projecting into chamber
170 aiding in the placement and retention of ampoule 180. Hollow body
160 may also include optional stop
175. In some embodiments, when an ampoule is inserted in the chamber, it is seated against
the stop helping to position the ampoule relative to the lever. Although not shown,
in some embodiments, a screen or other filtering means may be located near open end
174 preventing shards of the crushed ampoule from reaching pad
178.
[0022] Hollow body
110 includes handle
116 which can be manually gripped during use. Here, wall
160 has first thickness,
T1. In crush region
114, located adjacent foot
136, wall
160 has second thickness,
T2, which is less than first thickness,
T1. Hollow body
110 may include optional step
111 transitioning between handle
116 and crush region
114.
[0023] Generally, first thickness,
T1, is selected to provide the desired mechanical integrity and may depend on known
factors such as the choice of material and the design of the applicator. For example,
for a given material, the wall should be of sufficient thickness to prevent crushing
the ampoule when the handle is gripped during normal use. In addition, the thickness
should be sufficient to prevent shards of the broken ampoule from penetrating the
wall. Generally, first thickness
T1 is at least 1 mm, e.g., at least 2 mm. In some embodiments, thickness
T1 is no greater than 5 mm, e.g., no greater than 4 mm.
[0024] Generally, second thickness,
T2, is selected to reduce the force required to deform the wall in crush region
114. As the applicator is often operated with a single hand, the grip is depressed by
thumb. Given the wide range of thumb strength for potential operators, it can be desirable
to minimize the force required to depress the grip, compress the wall, and fracture
the ampoule. However, the second thickness should still be adequate to minimize or
prevent unintended crushing and to retain any shards of broken ampoule. Generally,
the ratio of
T2 over
T1 is less than 1. In some embodiments, the ratio of
T2 over
T1 is no greater than 0.9, no greater than 0.7, or even no greater than 0.5. In some
embodiments, the ratio of
T2 over
T1 is at least 0.2, in some embodiments, at least 0.4.
[0025] Generally, the length of crush region
114 should be longer than the length of foot
136. In some embodiments, crush region extends from handle
116 to a location near or at open end
172. In some embodiments, crush region
114 may end at stop
175.
[0026] In some embodiments, the crush region may extend throughout the circumference of
the applicator. However, in some embodiments, the walls may not be thinned throughout
the circumference of the hollow body. For example, in some embodiments, the wall in
support region
115 may be thicker than in crush region
114. In some embodiments, the wall in support region
115 may have a third thickness,
T3, which is greater than the fist thickness,
T1. In some embodiments, the ratio of
T3 over
T1 is at least 1.1, e.g., at least 1.2, or even at least 1.3. Generally, the circumferential
width of the crush region should be greater than the width of the foot. In some embodiments,
the crush region extends at least +/- 30 degrees from the foot, in some embodiments,
at least +/- 60 degrees, or even +/- 90 degrees. Generally the support region would
encompass the remaining circumference of the hollow body.
[0027] A larger view of exemplary lever
130 is shown in
FIG. 3. Hinge
132 connects to and is integral with hollow body
110 at first location
142. The hinge extends from the hollow body at an angle terminating at second location
144 corresponding to the location of second truss
155. Grip
134 continues the lever from second location
144 to third location
146 at a distance
H from the hollow body. Foot
136 is connected to, and integral with hollow body
110. First truss
151 extends from third location
146 to foot
136 forming angle
A with wall
160. Brace
157 connects hinge
132 and second truss
155.
[0028] While there is some flexibility in the design of the lever, the present inventors
have discovered certain dimensions which are important to ease of use and functionality.
FIG. 4a illustrates a cross section of the lever of
FIG. 3, showing its position before crushing ampoule
170. FIG. 4b illustrates a cross section of the lever of
FIG. 3, showing its position after crushing ampoule
170 producing shards
171. Angle
A and height
H should be selected such that when grip
134 is depressed, the travel of foot
136 is sufficient to compress wall
160 in crushing region
114 and fracture ampoule
170 before grip
134 contacts wall
160 in handle region
116. By increasing the angle
A, sufficient distance
H can be achieved without requiring a grip of unwieldy length. In some embodiments,
angle
A is greater than 30 degrees, e.g., greater than 40 degrees. If angle
A is too steep, however, it may be difficult to actuate the lever. In some embodiments,
angle
A is no greater than 60 degrees, e.g., no greater than 50 degrees.
[0029] Distance,
H, will be somewhat dependent on the diameter of the chamber and ampoule, as the foot,
and therefore the grip, must be capable of travelling a sufficient distance in order
to crush the ampoule. In some embodiments,
H is greater than 0.5 times the diameter of the chamber, e.g., at least 1 times the
diameter of the chamber, or even at least 1.5 times the diameter of the chamber. In
some embodiments, height H is at least 10 mm, e.g., at least 20 mm. In some embodiments,
height H is no greater than 40 mm, e.g., no greater than 30 mm.
[0030] When grip
134 is depressed with applied force
F1, lever
130 operates as a second degree lever applying a crushing force
F2 at foot
136. Crushing force
F2 can be enhanced relative to applied force
F1 by appropriate selection of lengths
L1 and
L2. L1 is the distance between first location
142 where hinge
132 is connected to the wall and the center of foot
136. L2 is the distance from first location
142 to third location
146 at the end of grip
134. Generally, the ratio of
F2 over
F1 is proportional to the ratio of
L2 over
L1. In some embodiments, the ratio of
L2 over
L1 is at least 1.5, e.g., at least 1.8. In some embodiments, the ratio of
L2 over
L1 is no greater than 3, e.g., no greater than 2.5.
[0031] In order to concentrate the crushing force and reduce the applied force required
to break ampoule
170, it may be desirable to decrease the size of foot
136. However, if the area of foot
136 is too small, lever
130 may flex to the side when compressed hindering operation. This problem has been reduced
in prior art constructions through the use of rigid, high modulus materials. However,
alternative approaches are required when flexible, lower modulus materials are used.
[0032] Referring to
FIGS. 1 and 3, brace
157 assists in stabilizing the lever. In some embodiments, the major axis of brace
157 is substantially parallel to the major axis of elongated hollow body
110. For example, in some embodiments, the major axis of brace
157 and the major axis of elongated hollow body
110 are within +/- 20 degrees from parallel, e.g., +/- 10 degrees, or even +/- 5 degrees
from parallel.
[0033] In some embodiments, trusses
151 and
155 may merge at a common location at the foot. Alternatively, as shown in
FIG. 3, in some embodiments, each of the trusses may connect to foot
136 at spaced-apart locations providing further stability to the lever.
[0034] An end view of lever
130 according to some embodiments of the present disclosure is shown in
FIG. 5. The top of grip
134 has a first width
W1 where it terminates at third location
146. Generally, the top surface of grip
134, including its width, is selected to provide a comfortable and stable base form the
application of force to crush the ampoule. In general, the size may be selected to
correspond to the expected range of widths of the human thumb. In some embodiments,
width
W1 is at least 5 mm, e.g., at least 10 mm. In some embodiments, width
W1 is no greater than 25 mm, e.g., no greater than 20 mm.
[0035] In some embodiments, in order to further concentrate the applied force onto foot
136, first truss
151 may be tapered. That is, the width of first truss
151 may decrease from first width
W1 where the truss connects to the grip to second width
W2 where the truss connects to foot
136. Generally, the ratio of
W2 over
W1 is less than 1, e.g., less than 0.8, less than 0.5 or even less than 0.4. The minimum
desirable width at foot
136 will be influenced by the desirable stability of the lever, as the narrower the foot
the more likely undesirable sidewise flexing may occur. In some embodiments, width
W2 is at least 2 mm, e.g., at least 3 mm. In some embodiments, width
W2 is no greater than 8 mm, e.g., no greater than 4 mm.
[0036] In some embodiments, the width of the second truss is also tapered as the second
truss approaches the foot. For example, in some embodiments, the second truss tapers
from a third width proximate the second location to a fourth width proximate the foot;
wherein the ratio of the fourth width over the third width is less than 1.
[0037] Along with its width, the length of foot
136 determines the pressure applied to crush the ampoule, with a smaller foot creating
more pressure per unit force applied. As with the width, mechanical robustness and
lever stability affect the minimum foot length. However, the addition of the brace
connecting the hinge to the second truss provides sufficient additional stability
that smaller foot sizes can be used without the instability noted with previous designs.
In particular, the brace helps prevent the lever from flexing sidewise when force
is applied, despite the use of a smaller foot. As a result of a smaller foot, the
applied force can be concentrated onto a smaller crush area, resulting in lower applied
forces required to crush the ampule.
[0038] In some embodiments, the length of the foot is at least 1 mm, e.g., at least 2 mm.
In some embodiments, the length of the foot is no greater than 10 mm, e.g., no greater
than 5 mm, or even no greater than 3 mm. In some embodiments, the area of the foot
(length multiplied by width) is no greater than 20 square millimeters, e.g., no greater
than 10 square millimeters. In some embodiments, the area of the foot is at least
5 square millimeters, e.g., at least 8 square millimeters.
[0039] Generally, the levers of the present disclosure include a hinge, a grip, first and
second trusses, and a brace. As shown in
FIGS. 6a and
6b, in some embodiments, the lever may include additional features. For example, referring
to
FIG. 6a, liquid applicator
200 includes lever
230 comprising hinge
232, grip
234, and foot
236. Hinge
232 extends from first location
242, which is integral to hollow body
210, to second location
244. Grip
234 continues the lever from second location
244 to third location
246. Trusses
251 and
255 connect hinge
232 and grip
234 to foot
236. First truss
251 extends from third location
246 to foot
236. Similarly, second truss
255 extends from second location
244 to foot
236. Brace
257 connects hinge
232 and second truss
255.
[0040] Lever
230 further includes third truss
253 located between first truss
251 and second truss
255. Third truss
253 extends from foot
236 to fourth location
248, which is between second location
244 and third location
246. In some embodiments, the third truss provides additional stability to the lever during
a crushing operation. In some embodiments, the third truss contributes to concentrating
the crushing force onto the foot.
[0041] Additional trusses may be included in the lever. For example, referring to
FIG. 6b, liquid applicator
300 includes lever
330 comprising hinge
332, grip
334, and foot
336. Hinge
332 extends from first location
342, which is integral to hollow body
310, to second location
344. Grip
334 continues the lever from second location
344 to third location
346. Trusses
351 and
355 connect hinge
332 and grip
334 to foot
336. First truss
351 extends from third location
346 to foot
336. Similarly, second truss
355 extends from second location
344 to foot
336. Brace
357 connects hinge
332 and second truss
355. In some embodiments, lever
330 includes one or more additional trusses, e.g., trusses
352. The locations and angles of such additional trusses may be selected based on desired
enhancements such as stability and force concentration.
[0042] A wide variety of pads are known, including sponges and fabrics. Generally, such
pads have been cylindrical or rectangular in shape with substantially smooth surfaces,
i.e., although the surface may have some small scale roughness associated with the
material selected, no large scale variations in the thickness of the applicator are
present. All such applicators are suitable for use in the various embodiments of the
present disclosure. However, in some embodiments, the present inventors have discovered
that an undulating pad may provide additional benefits in the uniform application
of liquids to surfaces.
[0043] Liquid applicators according to the present disclosure were molded from linear low
density polyethylene. The required crush force of these unitary structures was compared
to the crush force for a commercially available applicator.
[0044] Applicators were placed in an adjustable block and held at a 45 degree angle with
the grip portion of the lever in a horizontal position. A pin was mounted vertically
in an Instron™ Test Machine such that when the head was lowered the pin would contact
the outermost region of the grip. With the applicator held firmly in place, the pin
was lowered at 50 millimeters per second and the force required to crush the glass
ampoule within the applicator was recorded.
[0045] First, a commercial product was tested. The 8635 DuraPrep™ applicator available from
3M Company, St. Paul, Minnesota, was a two part construction with the hollow body
formed from linear low density polyethylene, and a separate lever formed of a rigid
polycarbonate. Based on fourteen tests, the average applied force for this commercial
product was 48 +/- 8 Newton. Commercial experience indicates that this is an acceptable
force.
[0046] Two applicators according to embodiments of the present disclosure were prepared,
as illustrated in FIGS. 1 and 3. These examples were prepared from linear low density
polyethylene (flexural modulus of 317 MPa). For both Examples 1 and 2, the foot extended
2.5 mm along the length of the applicator. The width of the foot was 6.4 mm for Example
1, resulting in a foot area of 16 square millimeters. The width of the foot was reduced
to 3.8 mm for Example 2, resulting in a foot area of 9.5 square millimeters. Based
on fifteen tests for each, the average applied force for was 53 +/- 9 Newton for Example
1, and 46 +/- 8 Newton for Example 2.
[0047] Generally, the applicators of the present disclosure can be made by known methods.
In some embodiments, injection molding may be used. A variety of materials may be
used to form the applicators. In some embodiments, applicators formed of low flexural
modulus materials such as low density polyethylene may be used. For example, in some
embodiments, materials having a flexural modulus of no greater than 500 Mpa, e.g.,
no greater than 400 MPa, or even no greater than 350 MPa may be used.
[0048] Various modifications and alterations of this invention will become apparent to those
skilled in the art without departing from the scope of this invention.